Factors affecting triadimefon degradation in soils

Area of Science:

• Environmental Chemistry
• Soil Science
• Agrochemicals

Background:

• Triadimefon is a widely used fungicide.
• Understanding its environmental fate is crucial for risk assessment.
• Soil properties significantly influence pesticide degradation.

Purpose of the Study:

• To investigate the degradation of triadimefon in different soil types (mollisol, inseptisol).
• To determine the effects of soil moisture, temperature, cow manure amendment, and soil sterilization on triadimefon degradation.
• To assess the impact of triadimefon on soil enzyme activities.

Main Methods:

• Studied triadimefon degradation under varying moisture (flooded vs. nonflooded) and temperature (27°C vs. 35°C) conditions.
• Investigated the role of cow manure amendment (5%) and soil sterilization.
• Analyzed degradation pathways and quantified triadimefon persistence.
• Assessed soil phosphatase and dehydrogenase activities.

Main Results:

• Soil moisture dictates degradation pathways: reduction to triadimenol in nonflooded soils and metabolism to a diol derivative in flooded soils.
• In nonflooded soils, triadimefon was more persistent in high organic carbon soils (mollisol), with cow manure increasing persistence.
• In flooded soils, higher organic carbon decreased persistence, and cow manure enhanced degradation.
• Degradation was faster at 35°C than 27°C and occurred only in non-sterile soils, indicating microbial mediation.
• Triadimefon did not affect phosphatase activity but significantly reduced dehydrogenase activity, especially in mollisol.

Conclusions:

• Microbial activity is essential for triadimefon degradation.
• Soil moisture and organic matter content are key factors influencing triadimefon persistence and degradation pathways.
• Cow manure amendment has contrasting effects on triadimefon degradation depending on soil moisture conditions.
• Triadimefon impacts soil microbial health by reducing dehydrogenase activity.